Energy Resources, Thermal, Hydel and Renewable

Why Energy Resources Matter in CDS

Almost every CDS General Studies paper carries at least one or two questions on energy — sometimes a simple fact (which state leads in wind power), sometimes a matching set (link a power plant to its river or state). The topic rewards a clear mental map far more than rote learning, because the questions test categories and locations rather than long definitions.

Energy is the lifeblood of every economy. Agriculture, industry, transport and homes all run on it, so a country’s level of development is closely linked to how much energy it consumes per person. India is the world’s third-largest energy consumer, yet its per-capita consumption is still well below the global average — a fact examiners like to use as a statement to verify.

Two Ways to Classify Energy

Energy sources are grouped in two overlapping ways. Keeping the two systems distinct prevents most mistakes.

By how long they last

• Renewable (inexhaustible): replenished by nature in a human timescale — solar, wind, hydel, tidal, geothermal and biomass.
• Non-renewable (exhaustible): formed over millions of years and finite — coal, petroleum, natural gas and nuclear minerals like uranium.

By how commonly they are used

• Conventional: in long, widespread use — coal, petroleum, natural gas, firewood and hydel power.
• Non-conventional (alternative): newer and being actively promoted — solar, wind, biogas, geothermal, tidal and nuclear.

Coal: India's Energy Backbone

Coal is the most abundant fossil fuel in India and supplies the bulk of electricity, since most thermal plants burn it. It is a sedimentary rock formed from buried plant matter over millions of years.

The four ranks of coal, in increasing carbon content and heating value, are:

1. Peat — lowest grade, high moisture, low carbon.
2. Lignite — brown coal; Neyveli in Tamil Nadu is the chief deposit.
3. Bituminous — the most widely used grade for power and industry.
4. Anthracite — highest grade, hard, over 80% carbon; rare in India (small amounts in Jammu & Kashmir).

Most Indian coal is Gondwana coal (about 250 million years old), found in the river valleys of the peninsula, while younger Tertiary coal occurs in the north-east. Major coalfields include Jharia, Bokaro and Raniganj (the Damodar valley belt of Jharkhand and West Bengal), Korba (Chhattisgarh), Singrauli (Madhya Pradesh) and Talcher (Odisha).

Petroleum and Natural Gas

Petroleum (mineral oil) is found in the pore spaces of sedimentary rocks, usually trapped in folded anticline structures with natural gas above the oil and water below. It is refined to give petrol, diesel, kerosene, LPG and many petrochemicals.

India’s main oil-producing regions are:

• Mumbai High — the largest offshore field, in the Arabian Sea off Maharashtra.
• Gujarat — Ankleshwar, Kalol and the Cambay basin.
• Assam — Digboi (India’s oldest oilfield and refinery), Naharkatiya and Moran.
• Krishna-Godavari (KG) basin — offshore eastern coast, a major gas source.

Natural gas is the cleanest fossil fuel, used as CNG in vehicles, as PNG in homes, and as feedstock for fertilisers. It is found alone or along with oil. India still imports most of its crude oil, which makes energy security a recurring exam theme.

Thermal Power: How and Where

Thermal power is generated by burning a fuel — coal, lignite, oil or gas — to boil water into high-pressure steam that spins a turbine connected to a generator. It supplies the largest share of India’s installed capacity, mainly because coal is plentiful.

Thermal plants are sited either at the coalfield (to save on transporting bulky coal) or near a large demand centre with good transport links. Major coal-based stations include Singrauli (UP), Korba (Chhattisgarh), Ramagundam (Telangana), Talcher (Odisha) and Vindhyachal (MP), several run by NTPC.

Hydel (Hydroelectric) Power

Hydel power uses the potential energy of falling or fast-flowing water to turn turbines. It is renewable, clean and cheap to run, although dams have high initial cost and environmental and displacement concerns.

A site needs a steady water supply and a good head (vertical drop), so plants cluster on rivers fed by the Himalayas or in the high-rainfall Western Ghats and north-east. Landmark multipurpose projects, important for CDS, include:

• Bhakra-Nangal — on the Sutlej (Punjab–Himachal); the Bhakra dam is among India’s tallest.
• Hirakud — on the Mahanadi (Odisha); one of the world’s longest dams.
• Nagarjuna Sagar — on the Krishna (Telangana–Andhra Pradesh).
• Tehri — on the Bhagirathi (Uttarakhand); a very tall dam.
• Sardar Sarovar — on the Narmada (Gujarat).

Nuclear Power and Atomic Minerals

Nuclear (atomic) power releases energy by splitting heavy atoms (fission) of uranium or thorium; the heat boils water and drives a turbine, like a thermal plant but with a nuclear ‘fuel’. It is classed as non-conventional but non-renewable, since the fuel minerals are finite.

India is rich in thorium, found in the monazite sands of the Kerala coast, which underpins the long-term three-stage nuclear programme. Uranium is mined mainly at Jaduguda (Jharkhand).

Operating nuclear power stations to remember include Tarapur (Maharashtra) — India’s first, Rawatbhata (Rajasthan), Kakrapar (Gujarat), Kaiga (Karnataka), Kalpakkam (Tamil Nadu) and Kudankulam (Tamil Nadu) — the largest, built with Russian help.

Non-Conventional and Renewable Sources

Because fossil fuels pollute and run out, India is pushing hard on clean, inexhaustible sources. The major non-conventional types are:

• Solar: sunlight converted to electricity by photovoltaic cells or to heat by collectors. Rajasthan and Gujarat lead because of clear skies and desert space; Bhadla (Rajasthan) is among the world’s largest solar parks.
• Wind: moving air spins turbines. Tamil Nadu (Muppandal) and Gujarat lead; India has large installed wind capacity.
• Biomass and biogas: energy from crop waste, dung and plants; biogas (gobar gas) is widely used in villages.
• Geothermal: heat from inside the Earth, tapped at hot springs such as Manikaran (Himachal) and the Puga valley (Ladakh).
• Tidal and wave: energy from sea movements; the Gulf of Khambhat and Gulf of Kachchh (Gujarat) have the best tidal potential.

Comparing Sources and a Worked Example

For CDS it helps to compare the four big electricity sources on a few simple axes:

• Thermal: non-renewable; cheap to build and flexibly located; highly polluting.
• Hydel: renewable; high build cost but very low running cost; clean, but displacement and silting issues.
• Nuclear: non-renewable; very high build cost; low routine pollution but waste and safety concerns.
• Solar/Wind: renewable and clean; falling costs but intermittent (depend on sun and wind).

A common statement question contrasts initial cost with running cost: thermal is cheap to set up but costly to fuel, while hydel and renewables are costly to set up but cheap to run. The pollution ranking is another favourite — coal-thermal is the dirtiest, natural gas the cleanest fossil fuel, and solar/wind essentially pollution-free in operation.

This two-question method — ‘does it run out?’ and ‘is it long-established?’ — lets you place any source correctly. Try it on hydel: it does not run out (renewable) but is long-established (conventional).

Common Mistakes to Avoid

Other traps: thinking thermal power is clean, calling lignite a high-grade coal (it is low-grade), and confusing uranium (Jaduguda) with thorium (Kerala monazite sands).

Previous-Year Style Practice

Quick Revision

Lock these categories and locations in, and energy questions become safe, scoring marks in your CDS Geography paper with The Cavalier.